Apparatus for detecting and counting damaged filaments in yarn



Dec. 28, 1954 Fiied July 23, 1951 GARRETT 2,698,418

[1 A APPARATUS FOR DETECTING AND COUNTING DAMAGED FILAMENTS IN YARN 2 Sheets-Sheet l /n venfor:

Dona/d Arf/rur' ctr/e11, By W, M 4 M Afro/we ya.

Dec. 28, 1954 D. A. GARRETT 2,698,413

' APPARATUS FOR DETECTING AND COUNTING DAMAGED FILAMENTS IN YARN Filed July 23, 1951 2 Sheets-Sheet 2 Doha/d Ari/m! Gar/e77,

United States Patent APPARATUS FOR DETECTING AND COUNTING DAMAGED FILAMENTS IN YARN Donald Arthur Garrett, Blackley, Manchester, England,

assignor to Imperial Chemical Industries Limited, a corporation of Great Britain Application July 23, 1951, Serial No. 238,067

Claims priority, application Great Britain August 8, 1950 3 Claims. (Cl. 324-61) This invention relates to a method and apparatus for detecting and counting broken or looped filaments in running continuous-filament yarn.

According to the invention broken or looped filaments in running continuous-filament yarn are detected and/ or counted by a method which comprises running the yarn freely through two small holes, one in each plate of a two-plate electrical condenser, of which one plate is fixed and the other is displaceable from its normal position, under the influence of a very small force, in a direction approximately perpendicular to its plane, and using the change in capacity of the condenser consequent upon the movement of the free plate caused by a projecting broken or looped filament to actuate a capacity-sensitive relay coupled to a suitable counter unit.

Also according to the invention there is provided an apparatus for detecting and/ or counting broken or looped filaments in running continuous-filament yarn which comprises a two-plate air-dielectric electrical condenser having one plate fixed and the other plate suspended so as to be displaceable from its normal position, under the influence of a very small force, in a direction approximately perpendicular to its plane, and means for running the yarn freely through two opposed holes in the two plates, of diameter slightly greater than that of the yarn.

When using the apparatus of this invention for detecting and/ or counting broken or looped filaments the electrical condenser is connected electrically to a suitable device for detecting and/or counting changes in electrical capacity. Such a device may comprise for example a capacity-sensitive relay operating an electro-magnetic counter unit or a pen on a moving chart.

After each displacement, by the impact of a broken filament, of the suspended condenser plate, it may oscillate slightly about its steady position and cause repeated closing of the capacity-sensitive relay. It may therefore be necessary, in the event that the relay is set to operate a counter-unit, to arrange for the latter to have a dead period of say A to 2 seconds after each initial impulse during which it does not respond to further impulses from the relay.

Patented Dec. 28, 1954 "ice The invention may be illustrated by reference to the accompanying drawings in which Fig. l is a side elevation and Fig. 2 is a plan.

In the drawings 1 and 2 are pairs of freely running pulleys over which the yarn 3 is passed. The fixed plate 4 of the electrical condenser is mounted on a support 5 and is enclosed in a box made up of Perspex sides 6 and a metal top 7. The displaceable condenser plate 8 is suspended by a light-weight electrically-conducting suspension from two hooks 9 attached to the metal top 7. The separation of the condenser plates may be adjusted by means of screws 10. Electrical connection to the displaceable plate is made by means of a tag 11 mounted on the metal top 7 connection to the fixed plate is made by means of a screw 12 in the support 5.

The diameter of the hole in the displaceable condenser plate is chosen so as to exceed by approximately .01 inch the maximum diameter of the undamaged yarn. The diameter of the hole in the fixed plate is not critical and may be made as large as /s" for convenience in thread-- ing the yarn through the holes initially.

The sensitivity of the instrument depends upon the weight of the displaceable condenser plate and may be adjusted to suit the type of yarn under inspection, the speed of running, the proportion of broken filaments and so on.

What I claim is:

1. Apparatus for detecting broken or looped filaments in running continuous-filament yarn which comprises, a two-plate air-dielectric electrical condenser having one plate fixed and the other plate suspended so as to be displaceable from its normal position, under the influence of a very small force, in a direction approximately perpendicular to its plane, each of said plates having holes therein of a diameter slightly greater than that of the yarn opposed to each other, and means for running the yarn freely through the said opposed holes.

2. Apparatus for detecting broken or looped filaments in running continuous-filament yarn which comprises, a two-plate air-dielectric electrical condenser having one plate fixed and the other plate suspended so as to be displaceable from its normal position, under the influence of a very small force, in a direction approximately perpendicular to its plane and means to run continuous-filament yarn freely past and in loose contact with at least one edge of said suspended plate.

3. Apparatus as recited in claim 2 in which the said edge is an interior edge formed by a small hole in the said suspended plate.

References Cited in the file of this patent UNITED STATES PATENTS 

